Prosthetic heart valve having leaflet inflow below frame

ABSTRACT

Embodiments of a prosthetic heart valve are disclosed. An implantable prosthetic valve can include an annular frame having an inflow end, an outflow end and a central longitudinal axis extending from the inflow end to the outflow end. The valve can include a valvular structure including two or more leaflets, each of the two or more leaflets having a leaflet inflow edge positioned at least partially outside of the frame and a leaflet outflow edge positioned within the frame, wherein at least a portion of each of the leaflet inflow edges is unsupported by the frame.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/808,599, filed Nov. 9, 2017, which claims the benefit ofU.S. Provisional Patent Application No. 62/423,599, filed Nov. 17, 2016,both of which applications are incorporated herein by reference.

FIELD

The present disclosure concerns embodiments of a prosthetic heart valve.

BACKGROUND

The human heart can suffer from various valvular diseases. Thesevalvular diseases can result in significant malfunctioning of the heartand ultimately require replacement of the native valve with anartificial valve. There are a number of known artificial valves and anumber of known methods of implanting these artificial valves in humans.

Various surgical techniques may be used to replace or repair a diseasedor damaged valve. Due to stenosis and other heart valve diseases,thousands of patients undergo surgery each year wherein the defectivenative heart valve is replaced by a prosthetic valve. Another lessdrastic method for treating defective valves is through repair orreconstruction, which is typically used on minimally calcified valves.The problem with surgical therapy is the significant risk it imposes onthese chronically ill patients with high morbidity and mortality ratesassociated with surgical repair.

When the native valve is replaced, surgical implantation of theprosthetic valve typically requires an open-chest surgery during whichthe heart is stopped and patient placed on cardiopulmonary bypass (aso-called “heart-lung machine”). In one common surgical procedure, thediseased native valve leaflets are excised and a prosthetic valve issutured to the surrounding tissue at the valve annulus. Because of thetrauma associated with the procedure and the attendant duration ofextracorporeal blood circulation, some patients do not survive thesurgical procedure or die shortly thereafter. It is well known that therisk to the patient increases with the amount of time required onextracorporeal circulation. Due to these risks, a substantial number ofpatients with defective native valves are deemed inoperable becausetheir condition is too frail to withstand the procedure. By someestimates, more than 50% of the subjects suffering from valve stenosiswho are older than 80 years cannot be operated on for valve replacement.

Because of the drawbacks associated with conventional open-heartsurgery, percutaneous and minimally-invasive surgical approaches havebecome widely adopted in recent years. In one technique, a prostheticvalve is configured to be implanted in a much less invasive procedure byway of catheterization. For instance, U.S. Pat. Nos. 5,411,522 and6,730,118, which are incorporated herein by reference, describecollapsible transcatheter heart valves that can be percutaneouslyintroduced in a compressed state on a catheter and expanded in thedesired position by balloon inflation or by utilization of aself-expanding frame or stent.

An important design parameter of a transcatheter heart valve is theamount of mechanical interaction between the prosthetic frame or stentand the native anatomy at the annulus and left ventricle outflow tract(“LVOT”) level. It is desirable to reduce tissue trauma and/ormechanical stress in the native anatomy to avoid procedural-relatedinjuries, such as LVOT, aortic and/or annulus rupture, which may occurin the region of the aortic root and the LVOT during transcatheteraortic valve replacement.

SUMMARY

An exemplary embodiment of a prosthetic heart valve can include anannular frame having an inflow end, an outflow end and a centrallongitudinal axis extending from the inflow end to the outflow end. Theframe can include a valvular structure including two or more leaflets,each of the two or more leaflets having a leaflet inflow edge positionedat least partially outside of the frame and a leaflet outflow edgepositioned within the frame, wherein at least a portion of each of theleaflet inflow edges is unsupported by the frame. Some embodiments caninclude an inner skirt, wherein a first portion of the inner skirtextends circumferentially around the central longitudinal axis along aninner surface of the frame and a second portion of the inner skirtextends circumferentially around the central longitudinal axis outsideof the frame. In some embodiments, the portions of the leaflet inflowedges unsupported by the frame are connected to the second portion ofthe inner skirt.

Additionally and/or alternatively, the inner skirt can include a firstset of fibers that are sufficiently stiff to impede inward bending ofthe second portion due to systolic pressure gradient and blood flowingfrom the left ventricle to the aorta. In some embodiments, the first setof fibers run parallel to the central longitudinal axis. In someembodiments, the inner skirt includes a second set of fibers that runperpendicular to the first set of fibers, wherein the first set offibers are stiffer than the second set of fibers. In some embodiments,the first set of fibers include monofilaments. In some embodiments, theportions of the leaflet inflow edges unsupported by the frame eachinclude an apex portion of each leaflet. In some embodiments, the frameincludes at least two rows of cells defining openings having a length inan axial direction and a length of the portion of the inflow edgesunsupported by the frame is equal to or greater than the length of theopenings. Additionally and/or alternatively, some embodiments caninclude an outer sealing member mounted on the outside of the frame.

Additionally and/or alternatively, some embodiments can include an outersupport layer mounted on the outside of the frame having an inflow endportion that extends axially beyond the inflow end of the frame, and theportion of the leaflet inflow edges unsupported by the frame isconnected to the inflow end portion of the outer support layer.

Some embodiments of an implantable prosthetic valve can include anannular frame having an inflow end, an outflow end and a centrallongitudinal axis extending from the inflow end to the outflow end, aninner skirt, wherein a first portion of the inner skirt extendscircumferentially around the central longitudinal axis along an innersurface of the frame and a second portion of the inner skirt extendscircumferentially around the central longitudinal axis outside of theframe and a valvular structure including two or more leaflets, each ofthe two or more leaflets having a leaflet inflow edge positioned atleast partially outside of the frame and a leaflet outflow edgepositioned within the frame, wherein at least a portion of each of theleaflet inflow edges are connected to the second portion of the innerskirt.

In some embodiments, the inner skirt includes a first set of fibers anda second set of fibers that runs perpendicular to the first set offibers, wherein the first set of fibers is stiffer than the second setof fibers. In some embodiments, the frame includes a row of cellsdefining openings having a length in an axial direction and furtherwherein a length of the second portion is equal to or greater than thelength of the openings. In some embodiments, an outer skirt can beconnected to the second portion of the inner skirt. In some embodiments,the portions of the leaflet inflow edges unsupported by the frameinclude an apex portion of each leaflet.

Some embodiments of an implantable prosthetic valve can include anannular frame having an inflow end, an outflow end and a centrallongitudinal axis extending from the inflow end to the outflow end, asupport layer, wherein a first portion of the support layer extendscircumferentially around the central longitudinal axis along an outersurface of the frame and a second portion of the support layer extendscircumferentially around the central longitudinal axis axially beyondthe inflow end of the frame, and a valvular structure wherein at least aportion of the valvular structure is connected to the second portion ofthe support layer and is unsupported by the frame. In some embodiments,an outer skirt can be connected to the second portion of the supportlayer at an inflow end of the outer skirt. In some embodiments, thesupport layer includes a first set of fibers and a second set of fibersthat runs perpendicular to the first set of fibers, wherein the firstset of fibers is stiffer than the second set of fibers. In someembodiments, the valvular structure comprises a plurality of leafletsand the first set of fibers includes monofilaments. In some embodiments,the at least a portion of the valvular structure unsupported by theframe includes an apex portion of each leaflet.

The foregoing and other objects, features, and advantages of thedisclosure will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front view of an exemplary embodiment of a prostheticheart valve.

FIG. 2 shows a side view of the prosthetic heart valve of FIG. 1 withthe outer skirt removed to show an inner skirt and valvular structuremounted on the frame.

FIG. 3 shows a rotated front view of the prosthetic heart valve of FIG.2.

FIG. 4 shows an enlarged, partial cross-sectional view of a prostheticheart valve, according to one embodiment.

FIG. 5A shows an enlarged, partial cross-sectional view of a prostheticheart valve, according to one embodiment.

FIG. 5B shows a side view of an exemplary support layer shown inflattened configuration.

FIG. 6 shows a top plan view of the prosthetic heart valve of FIG. 1.

FIG. 7 shows a side view of an exemplary inner skirt shown in flattenedconfiguration.

FIG. 8 shows a side view of an exemplary leaflet shown in flattenedconfiguration.

FIG. 9 shows a side view of an exemplary outer skirt shown in flattenedconfiguration.

FIG. 10 shows a perspective view of an exemplary frame of the prostheticheart valve of FIG. 1.

FIG. 11 shows a side view of the frame of FIG. 10 shown in flattenedconfiguration.

FIG. 12 is a side view of the prosthetic valve of FIG. 1 in a collapsedconfiguration mounted on the balloon of a delivery apparatus.

DETAILED DESCRIPTION

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein.Features, integers, characteristics, compounds, chemical moieties orgroups described in conjunction with a particular aspect, embodiment orexample of the invention are to be understood to be applicable to anyother aspect, embodiment or example described herein unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The invention is notrestricted to the details of any particular embodiments. The inventionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, it shouldbe understood that this manner of description encompasses rearrangement,unless a particular ordering is required by specific language. Forexample, operations described sequentially may in some cases berearranged or performed concurrently. Moreover, for the sake ofsimplicity, the attached figures may not show the various ways in whichthe disclosed methods can be used in conjunction with other methods.

As used herein, the terms “a”, “an”, and “at least one” encompass one ormore of the specified element. That is, if two of a particular elementare present, one of these elements is also present and thus “an” elementis present. The terms “a plurality of” and “plural” mean two or more ofthe specified element.

As used herein, the term “and/or” used between the last two of a list ofelements means any one or more of the listed elements. For example, thephrase “A, B, and/or C” means “A”, “B,”, “C”, “A and B”, “A and C”, “Band C”, or “A, B, and C.”

As used herein, the term “coupled” generally means physically coupled orlinked and does not exclude the presence of intermediate elementsbetween the coupled items absent specific contrary language.

FIGS. 1 and 6 show side and top plan views, respectively, of aprosthetic heart valve 10 having an inflow end 80 and an outflow end 82,according to one embodiment. The illustrated prosthetic valve is adaptedto be implanted in the native aortic annulus, although in otherembodiments it can be adapted to be implanted in the other nativeannuluses of the heart (the mitral valve, pulmonary valve and triscupidvalve). The prosthetic valve 10 can have one or more of the followingcomponents: a stent, or frame, 12, a valvular structure 14 and an innerskirt, or sealing member, 16. The valve 10 can also include an outerskirt, or sealing member 18.

The valvular structure 14 can comprise three leaflets 20, collectivelyforming a valvular structure, which can be arranged to collapse in atricuspid arrangement, as best shown in FIG. 6. The lower edge ofvalvular structure 14 desirably has an undulating, curved scallopedshape. By forming the leaflets with this scalloped geometry, stresses onthe leaflets are reduced, which in turn improves durability of thevalve. Moreover, by virtue of the scalloped shape, folds and ripples atthe belly of each leaflet (the central region of each leaflet), whichcan cause early calcification in those areas, can be eliminated or atleast minimized. The scalloped geometry also reduces the amount oftissue material used to form the valvular structure 14, thereby allowinga smaller, more even crimped profile at the inflow end of the valve. Theleaflets 20 can be formed of pericardial tissue (e.g., bovinepericardial tissue), biocompatible synthetic materials, or various othersuitable natural or synthetic materials as known in the art anddescribed in U.S. Pat. No. 6,730,118, which is incorporated by referenceherein.

The bare frame 12 is shown in FIGS. 10 and 11. The frame 12 has aninflow end 22, an outflow end 24 and a central longitudinal axis 26extending from the inflow end 22 to the outflow end 24. The frame 12 canbe made of any of various suitable plastically-expandable materials(e.g., stainless steel, etc.) or self-expanding materials (e.g.,Nitinol) as known in the art. When constructed of aplastically-expandable material, the frame 12 (and thus the prostheticvalve 10) can be crimped to a radially compressed state on a deliverycatheter and then expanded inside a patient by an inflatable balloon orequivalent expansion mechanism. When constructed of a self-expandablematerial, the frame 12 (and thus the prosthetic valve 10) can be crimpedto a radially compressed state and restrained in the compressed state byinsertion into a sheath or equivalent mechanism of a delivery catheter.Once inside the body, the valve can be advanced from the deliverysheath, which allows the valve to expand to its functional size.

Suitable plastically-expandable materials that can be used to form theframe 12 include, without limitation, stainless steel, a nickel basedalloy (e.g., a cobalt-chromium or a nickel-cobalt-chromium alloy),polymers, or combinations thereof. In particular embodiments, frame 12is made of a nickel-cobalt-chromium-molybdenum alloy, such as MP35N™(tradename of SPS Technologies), which is equivalent to UNS R30035(covered by ASTM F562-02). MP35N™/UNS R30035 comprises 35% nickel, 35%cobalt, 20% chromium, and 10% molybdenum, by weight. It has been foundthat the use of MP35N to form frame 12 provides superior structuralresults over stainless steel. In particular, when MP35N is used as theframe material, less material is needed to achieve the same or betterperformance in radial and crush force resistance, fatigue resistances,and corrosion resistance. Moreover, since less material is required, thecrimped profile of the frame can be reduced, thereby providing a lowerprofile valve assembly for percutaneous delivery to the treatmentlocation in the body.

Referring to FIGS. 10 and 11, the frame 12 in the illustrated embodimentcomprises a first, lower row I of angled struts 28 arranged end-to-endand extending circumferentially at the inflow end of the frame; a secondrow II of circumferentially extending, angled struts 30; a third row IIIof circumferentially extending, angled struts 32; and a forth row IV ofcircumferentially extending, angled struts 34 at the outflow end of theframe 12. The forth row IV of angled struts 34 can be connected to thethird row III of angled struts 32 by a plurality of axially extendingwindow frame portions 36 (which define commissure windows 38) and aplurality of axially extending struts 40. Each axial strut 40 and eachframe portion 36 extends from a location defined by the convergence ofthe lower ends of two angled struts 34 to another location defined bythe convergence of the upper ends of two angled struts 32.

Each commissure window frame portion 36 mounts a respective commissure74 of the leaflet structure 14. As can be seen, each frame portion 36 issecured at its upper and lower ends to the adjacent rows of struts toprovide a robust configuration that enhances fatigue resistance undercyclic loading of the valve compared to known cantilevered struts forsupporting the commissures of the leaflet structure. This configurationenables a reduction in the frame wall thickness to achieve a smallercrimped diameter of the valve. In particular embodiments, the thicknessof the frame 12 measured between the inner diameter and outer diameteris about 0.48 mm or less.

The struts and frame portions of the frame collectively define aplurality of open cells of the frame. At the inflow end 22 of the frame12, struts 28 and struts 30 define a lower row of cells definingopenings 42. The second and third rows of struts 30 and 32,respectively, define an intermediate row of cells defining openings 44.The third and fourth rows of struts 32 and 34, along with frame portions36 and struts 40, define an upper row of cells defining openings 46. Theopenings 46 are relatively large and are sized to allow portions of thevalvular structure 14 to protrude, or bulge, into and/or through theopenings 46 when the frame 12 is crimped in order to minimize thecrimping profile.

The frame 12 can have other configurations or shapes in otherembodiments. For example, the frame 12 can comprise a plurality ofcircumferential rows of angled struts 28, 30, 32, 34 connected directlyto each other without vertical struts 40 or frame portions 36 betweenadjacent rows of struts, or the rows of struts 28, 30, 32, 34 can beevenly spaced with vertical struts 40 and/or frame portions 36 extendingtherebetween. In other embodiments, the frame can comprise a braidedstructure braided from one or more metal wires.

The inner skirt 16 can have a plurality of functions, which can includeto assist in securing the valvular structure 14 and/or the outer skirtto the frame 12 and to assist in forming a good seal between the valve10 and the native annulus by blocking the flow of blood below the loweredges of the leaflets. The inner skirt 16 can comprise a tough, tearresistant material such as polyethylene terephthalate (PET), althoughvarious other synthetic or natural materials can be used. The thicknessof the skirt desirably is less than 6 mil or 0.15 mm, and desirably lessthan 4 mil or 0.10 mm, and even more desirably about 2 mil or 0.05 mm.In particular embodiments, the skirt 16 can have a variable thickness,for example, the skirt can be thicker at its edges than at its center.In one implementation, the skirt 16 can comprise a PET skirt having athickness of about 0.07 mm at its edges and about 0.06 mm at its center.The thinner skirt can provide for better crimping performances whilestill providing good perivalvular sealing.

As noted above, the valvular structure 14 in the illustrated embodimentincludes three flexible leaflets 20 (although a greater or fewer numberof leaflets can be used). An exemplary leaflet 20 is shown in FIG. 8.Each leaflet 20 can have a reinforcing strip 58 secured (e.g., sewn) tothe inner surface of the lower edge portion 56. Each leaflet 20 in theillustrated configuration can have an upper (outflow) free edge 48extending between opposing upper tabs 50 on opposite sides of theleaflet 20. Below each upper tab 50 there can be a notch 52 separatingthe upper tab 50 from a corresponding lower tab 54. The lower (inflow)edge portion 56 of the leaflet extending between respective ends of thelower tabs 54 can include vertical, or axial, edge portions 60 onopposites of the leaflets extending downwardly from corresponding lowertabs 54 and a substantially V-shaped, intermediate edge portion 62having a smooth, curved apex portion 64 at the lower end of the leafletand a pair of oblique portions 66 that extend between the axial edgeportions 60 and the apex portion 64. The oblique portions 66 can have agreater radius of curvature than the apex portion 64. The leaflets canhave various other shapes and/or configurations in other embodiments.For example, the leaflets need not have a V-shaped or scalloped inflowedges and instead each leaflet can have a square or rectangular shapedefining a straight inflow edge.

The leaflets 20 can be sutured together to form the assembled valvularstructure 14, which can then be secured to the frame 12. For example,the leaflets 20 can be secured to one another at their adjacent sides toform commissures 74 of the valvular structure. A plurality of flexibleconnectors (not shown) can be used to interconnect pairs of adjacentsides of the leaflets and to mount the leaflets to the commissure windowframe portions 30, as further discussed below. The leaflets 20 canadditionally and/or alternatively be secured together via adjacentsub-commissure portions (not shown) of two leaflets that can be sutureddirectly to each other.

FIGS. 2 and 3 show the frame 12, the valvular structure 14 and the innerskirt 16 after securing the valvular structure 14 to the inner skirt 16and then securing these components to the frame 12. The inner skirt 16can be secured to the inside of frame 12 via sutures 68. The valvularstructure 14 can be attached to the inner skirt 16 via the one or morethin PET reinforcing strips 58 along the lower (inflow) edge portions 56of the leaflets 20. The reinforcing strips 58 collectively can form asleeve, which can enable a secure suturing and protect the pericardialtissue of the valvular structure 14 from tears. Valvular structure 14can be sandwiched between the inner skirt 16 and the thin PET strips 58.Sutures 70, which secure the PET strips and the valvular structure 14 toinner skirt 16, can be any suitable suture, such as an Ethibond suture.Sutures 70 desirably track the curvature of the bottom edge of valvularstructure 14 and are collectible referred to as scallop line 72. In lieuof or in addition to the strips 58 along the inner surface of theleaflets, reinforcing strips 58 can be positioned between the innerskirt 16 and the inflow edge portions 56 of the leaflets (FIG. 4).

As shown in FIGS. 2 and 3, portions of the inflow edges 56 of theleaflets 56 are positioned between diagonal lines defined by the struts28, 30 of the first and second circumferential rows of the struts. Insome embodiments, the inflow edges 56 of the leaflets 20 can track thediagonal lines defined by the struts 28, 30. In such embodiments, theportions of the inflow edges 56 above the inflow end of the frame can besutured to adjacent struts 28, 30.

The outflow end portion of the valvular structure 14 can be secured tothe window frame portions 36. In particular, each leaflet 20 can haveopposing tab portions, each of which is paired with an adjacent tabportion of another leaflet to form a commissure 74. As best shown inFIG. 1, the commissures 74 can extend through windows 38 of respectivewindow frame portions 36 and sutured in place. Further details of thecommissures 74 and a method for assembling the commissures and mountingthem to the frame are disclosed in U.S. Publication No. 2012/0123529,which is incorporated herein by reference. The inner skirt 16 canterminate short of the window frame portions 36 and does not extend theentire length of the frame 12. In alternative embodiments, the innerskirt 16 can extend the entire length or substantially the entire lengthof the frame 12 from below the inflow end 22 to the outflow end 24. Inother embodiments, the inner skirt 16 can extend up to the second row ofangled struts 30.

In particular embodiments, and as shown in FIGS. 1-3, the valvularstructure 14 can extend axially beyond the inflow end 22 of the frame 12such that at least a portion of the inflow edges 56 of each leaflet isnot supported by the frame 12. For example, the apex portions 64 of theleaflets 20 can extend axially beyond and can be unsupported by theframe 12. Additionally and/or alternatively, the oblique portions 66 andthe apex portions 64 can extend axially beyond and can be unsupported bythe frame 12. Additionally and/or alternatively, the intermediateportions 62, the oblique portions 66 and the apex portions 64 can extendaxially beyond and can be unsupported by the frame 12. Additionallyand/or alternatively, the vertical edge portions 60, the intermediateportions 62, the oblique portions 66 and the apex portions 64 can extendaxially beyond and can be unsupported by the frame 12. In someembodiments, a portion 76 of each leaflet extends below the inflow end22 of the frame a length L₁ that is equal to or greater than a length L₂of each cell opening 42 in the axial direction. In some embodiments, L₁can range between about 2 mm to 8 mm in length, with 4 mm being aspecific example. Additionally and/or alternatively, L₁ can be up to 12mm. In some embodiments, L₂ can range between about 3 mm to 5 mm inlength, with 4 mm being a specific example. Additionally and/oralternatively, L₂ can range between 2 mm to 7 mm.

Additionally and/or alternatively, as shown in FIG. 4, the inner skirt16 can include a first portion 84, also referred to as supportedportion, that extends circumferentially around the central longitudinalaxis of the prosthetic valve along an inner surface of the frame 12 anda second portion, also referred to as unsupported portion 78, at theinflow end 80 of the prosthetic valve 10. The unsupported portion 78 isunsupported by the frame 12. The unsupported portion 78 can extendcircumferentially around the central longitudinal axis of the prostheticvalve to form an unsupported circumference at the inflow end 80. Asshown in FIG. 4, the portion of each leaflet 20 that is not supported bythe frame 12 can be connected to the inner skirt 16. In someembodiments, a length L₃ of the unsupported portion 78 is equal to orgreater than the length L₂ of the openings 42. In some embodiments, L₃can be 2 mm to 3 mm longer than L₁. Additionally and/or alternatively,L₃ can range from the same length as L₁ to 5 mm longer than L₁. In someembodiments, L₃ can range between about 2 mm to 11 mm in length, with 6mm being a specific example. Additionally and/or alternatively, L₃ canbe up to 15 mm.

In some embodiments, as best shown in FIG. 7, the inner skirt 16 can bewoven from a first set of fibers 86, or yarns or strands, and a secondset of fibers 88, or yarns or strands. The first and set of fibers 86,88 can run perpendicular and parallel, respectively, to upper 90 andlower 92 edges of the inner skirt 16, or alternatively, they can extendat angles between 0 and 90 degrees relative to the upper and lower edges90, 92 of the inner skirt 16. The first set of fibers 86 can be stifferthan the second set of fibers 88. For example the first set of fibers 86can include monofilaments. The extra stiffness of the first set offibers 86 can provide support to the prosthetic leaflets 20 duringsystole. For example, the first set of fibers 86 can reinforce the innerskirt 16 to impede inward and/or outward folding or bending of theunsupported portion 78 of the inner skirt and/or the unsupportedportions of 76 of the leaflets that are unsupported by the frame 12 dueto systolic pressure gradient and blood flowing from the left ventricleto the aorta. In other embodiments, the fibers 86 can be thicker thanthe fibers 88 and/or axially extending reinforcing wires (extending inthe same direction as fibers 86) can be woven or secured to the skirt toincrease the axial stiffness of the skirt. The reinforcing wires can bemetal wires formed from a suitable biocompatible metal, such asstainless steel or Nitinol.

In some embodiments, the first set of fibers 86 and the second set offibers 88 can extend at angles of about 45 degrees relative to the upperand lower edges. The inner skirt 16 can be formed by weaving the fibersat 45 degree angles relative to the upper and lower edges of the fabric.Alternatively, the skirt can be diagonally cut from a vertically wovenfabric (where the fibers extend perpendicular to the edges of thematerial) such that the fibers extend at 45 degree angles relative tothe cut upper and lower edges of the skirt. The opposing short edges ofthe inner skirt can be non-perpendicular to the upper and lower edges.

FIG. 9 shows a flattened view of the outer skirt 18 prior to itsattachment to the inner skirt 16 and the frame 12. The outer skirt 18can be laser cut or otherwise formed from a strong, durable piece ofmaterial, such as woven PET, although other synthetic or naturalmaterials can be used. The outer skirt 18 can have a substantiallystraight lower edge 94 and an upper edge 96 defining a plurality ofalternating projections 98 and notches 100. Alternatively, the loweredge 94 of the outer skirt 18 can include openings similar to those onthe upper edge, or can include a separate row of holes adjacent to thestraight lower edge 94. As best shown in FIG. 1, the lower edge 94 ofthe outer skirt 18 can be secured to the lower edge 92 of the innerskirt 16 at the inflow end of the prosthetic valve, such as by sutures,welding, and/or an adhesive. In particular embodiments, the lower edge94 of the outer skirt 18 is tightly sutured or otherwise secured (e.g.,by welding or an adhesive) to the inner skirt 16.

The upper edge 96 of the outer skirt 18 desirably is secured to theframe 12 and/or the inner skirt 16 at spaced-apart locations around thecircumference of the frame 12. In the illustrated embodiment, forexample, the projections 98 of the outer skirt can be sutured to thestruts of the frame 12 and/or the inner skirt 16. As shown, the cornersof the projections 98 of the outer skirt 18 can be folded overrespective struts and secured with sutures 104 (FIG. 1). The notches 100can remain unattached to the inner skirt 16 and the frame 12. When thevalve 10 is deployed within the body (e.g., within the native aorticvalve), the outer skirt 18 can cooperate with the inner skirt 16 toprevent or at least minimize paravalvular leakage.

The absence of metal components of the frame or other rigid membersalong the inflow end portion of the prosthetic valve advantageouslyreduces mechanical compression of the native valve annulus (e.g., theaortic annulus) and the left ventricular outflow tract (when implantedin the aortic position), thus reducing the risk of trauma to thesurrounding tissue.

As shown in FIG. 5A, some embodiments of a prosthetic valve 10 do notinclude an inner skirt 16 and instead can include a support layer 110disposed radially between the frame 12 and the outer skirt 18. In thismanner, the support layer 110 and the outer skirt 18 form an outersealing member with the support layer 110 forming an inner wall or layerof the sealing member and the outer skirt forming an outer wall or layerof the sealing member. A first portion 112 of the support layer 110 canextend circumferentially around the central longitudinal axis of theprosthetic valve along an outer surface of the frame 12 and a secondportion 114 of the support layer 110 can extend circumferentially aroundthe central longitudinal axis axially beyond the inflow end 22 of theframe. The unsupported portions 76 of the leaflets can be connected tothe support layer 110 (e.g., by sutures, an adhesive, and/or welding)similar to the manner that the leaflets are connected to the inner skirtin the embodiment of FIG. 4. For example, the inflow edge portions 56can be sutured to reinforcing strips 58 and the support layer 110 withthe inflow edge portions 56 sandwiched between the support layer 110 andthe reinforcing strips 58. Additionally and/or alternatively,reinforcing strips 58 can be positioned between the inflow edge portions56 and the support layer 110 with sutures securing these layerstogether. Additionally and/or alternatively, the outer skirt 18 can beconnected to the second portion 114 of the support layer (e.g., bysutures, an adhesive, and/or welding).

The support layer 110 can have the same or similar size and shape as theinner skirt 16 and can be made of the same or similar materials as theinner skirt 16. For example, as shown in FIG. 5B, the support layer 110can be woven from a first set of fibers 116 and a second set of fibers118, or yarns or strands. The first and second set of fibers 116, 118can run perpendicular and parallel, respectively, to upper and loweredges 120, 122 of the support layer 110, or alternatively, they canextend at angles between 0 and 90 degrees relative to the upper andlower edges 120, 122 of the support layer. The first set of fibers 116can be stiffer than the second set of fibers 118. For example the firstset of fibers 116 can include monofilaments, reinforcing wires and/orthicker fibers than the fibers 118. The extra stiffness of the first setof fibers 116 can provide support to the prosthetic leaflets 20 duringsystole. For example, the first set of fibers 116 can reinforce thesupport layer 110 to impede inward and/or outward folding or bending ofthe lower portion 114 and the unsupported portions 76 of the leafletsdue to systolic pressure gradient and blood flowing from the leftventricle to the aorta.

In alternative embodiments, the prosthetic valve 10 can include an innerskirt 16 and an outer support layer 110.

FIG. 12 shows the prosthetic valve 10 in a radially compressed state fordelivery into a patient's body on a delivery catheter 200. As shown, theprosthetic valve 10 can be crimped on a balloon 202 of the deliverycatheter 200. In the delivery configuration, the outer skirt 18 can befolded against the outer surface of the frame 12. When deployed insidethe body (e.g., after being released from the sheath of the deliverycatheter), the stent 12 and the outer skirt 18 can radially expand, suchas by inflating the balloon 202.

In view of the many possible embodiments to which the principles of thedisclosed technology may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the disclosureand should not be taken as limiting the scope of the disclosure. Rather,the scope of the disclosure is defined by the following claims. Itherefore claim as my disclosure all that comes within the scope andspirit of these claims.

I claim:
 1. An implantable prosthetic valve for replacing a native valveof the heart, the prosthetic valve comprising: an annular frame havingan inflow end, an outflow end and a central longitudinal axis extendingfrom the inflow end to the outflow end, wherein the frame is expandablefrom a radially compressed state to a radially expanded state in whichthe prosthetic valve engages an annulus of the native valve; a valvularstructure including two or more leaflets, each of the two or moreleaflets having a leaflet inflow edge positioned at least partiallyoutside of the frame and a leaflet outflow edge positioned within theframe, wherein at least a portion of each of the leaflet inflow edges isunsupported by the frame; and an inner skirt, wherein a first portion ofthe inner skirt extends circumferentially around the centrallongitudinal axis along an inner surface of the frame and a secondportion of the inner skirt extends circumferentially around the centrallongitudinal axis outside of the frame.
 2. The valve of claim 1, whereinthe inner skirt includes a first set of fibers that are sufficientlystiff to impede inward bending of the second portion due to systolicpressure gradient and blood flowing from the left ventricle to theaorta.
 3. The valve of claim 2, wherein the first set of fibers runparallel to the central longitudinal axis.
 4. The valve of claim 2,wherein the inner skirt includes a second set of fibers that runperpendicular to the first set of fibers, wherein the first set offibers are stiffer than the second set of fibers.
 5. The valve of claim2, wherein the first set of fibers include monofilaments.
 6. The valveof claim 1, wherein the portions of the leaflet inflow edges unsupportedby the frame each include an apex portion of each leaflet.
 7. The valveof claim 1, wherein the frame includes at least two rows of cellsextending circumferentially around the central longitudinal axis andwherein the cells of the at least two rows of cells define openings, theopenings having a length in an axial direction and wherein a length ofthe portion of the inflow edges unsupported by the frame is equal to orgreater than the length of the openings.
 8. The valve of claim 1,further comprising an outer sealing member mounted on the frame.
 9. Animplantable prosthetic valve for replacing a native valve of the heart,the prosthetic valve comprising: an annular frame having an inflow end,an outflow end and a central longitudinal axis extending from the inflowend to the outflow end, wherein the frame is expandable from a radiallycompressed state to a radially expanded state in which the prostheticvalve engages an annulus of the native valve; an inner skirt, wherein afirst portion of the inner skirt extends circumferentially around thecentral longitudinal axis along an inner surface of the frame and asecond portion of the inner skirt extends circumferentially around thecentral longitudinal axis outside of the frame; and a valvular structureincluding two or more leaflets, each of the two or more leaflets havinga leaflet inflow edge positioned at least partially outside of the frameand a leaflet outflow edge positioned within the frame, wherein at leasta portion of each of the leaflet inflow edges are connected to thesecond portion of the inner skirt.
 10. The valve of claim 9, wherein theinner skirt includes a first set of fibers and a second set of fibersthat runs perpendicular to the first set of fibers, wherein the firstset of fibers is stiffer than the second set of fibers.
 11. The valve ofclaim 9, wherein the frame includes a row of cells defining openingshaving a length in an axial direction and further wherein a length ofthe second portion is equal to or greater than the length of theopenings.
 12. The valve of claim 9, further comprising an outer skirtconnected to the second portion of the inner skirt.
 13. The valve ofclaim 9, wherein the portions of the leaflet inflow edges unsupported bythe frame include an apex portion of each leaflet.
 14. An implantableprosthetic valve for replacing a native valve of the heart, theprosthetic valve comprising: an annular frame having an inflow end, anoutflow end and a central longitudinal axis extending from the inflowend to the outflow end, wherein the frame is expandable from a radiallycompressed state to a radially expanded state in which the prostheticvalve engages an annulus of the native valve; and a valvular structureincluding two or more leaflets, each of the two or more leaflets havinga leaflet inflow edge positioned at least partially outside of the frameand a leaflet outflow edge positioned within the frame, wherein at leasta portion of each of the leaflet inflow edges is unsupported by theframe; wherein the frame includes at least two rows of cells extendingcircumferentially around the central longitudinal axis and wherein thecells of the at least two rows of cells define openings, the openingshaving a length in an axial direction and wherein a length of theportion of the inflow edges unsupported by the frame is equal to orgreater than the length of the openings.